Respuesta :

a group of words established by usage as having a meaning not deducible from those of the individual words 
synonyms:language, mode of expression, turn of phrase, style, speech, locution, diction, usage, phraseology, phrasing, phrase, vocabulary, terminology, parlance, jargon, argot, cant, patter, tongue, vernacula
AnimeBrainly
Idioms are "a group of words used to have a meaning that cannot be expressed by individual words"

hope this helps